I've received some new brachiopod specimens from Morocco recently and this Rhipidomella sp. is one of them. It's a large, rounded shell with fine radial ribbing on the surface. The pedicle valve is a bit more convex than the brachial valve. The specimen comes from El Mrakib near Alnif in Morocco. I don't have specifics as to the formation (I suspect the Taboumakhlouf Formation) but the local rocks in which it was found are Emsian to Givetian in age (Devonian). I have not yet been able to locate any literature which details this genera from Morocco so at this time I cannot give it a species name.
Brachial valve
Anterior
Pedicle valve
Posterior
Profile
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Saturday, April 18, 2015
Thursday, April 16, 2015
Devonogypa spinulosa brachiopod from Morocco
I've received some new brachiopod specimens from Morocco recently and this Gypidulid is one of them. The shell is about as wide as it is long with very unequal valves. The pedicle valve is very convex and curved while the brachial valve is only slightly convex. There is no sulcus in the shell and it is smooth except for some very fine concentric growth lines. I believe this should be called Devonogypa spinulosa after reading the paper, Middle Devonian brachiopods from the southern Maïder (eastern Anti- Atlas, Morocco). Halamski, A.T. and Baliński, A., 2013. Annales Societatis Geologorum Poloniae, 83: 243–307 since it seems to match both the description and the specimens illustrated in the plates. Within the paper the authors refer to this species as coming from outcrops of the Taboumakhlouf Formation (Devonian, Eifelian to Givetian stage) on El Mrakib (a mountain near Alnif) and the specimens I received came from there as well.
Brachial valve (note the spirorbis epibiont on the surface)
Anterior
Pedicle valve
Posterior
Profile
Brachial valve (note the spirorbis epibiont on the surface)
Anterior
Pedicle valve
Posterior
Profile
Tuesday, April 14, 2015
Digonella digona brachiopod from Ranville, France
I've featured the brachiopod Digonella digona on my blog previously, about four years ago, with specimens that came from Luc sur Mer, Calvados Department, France. The specimen below comes from a quarry near Ranville, which is inland and south from Luc sur Mer. The fossil is preserved with a black colored calcite compared to the tan and grey of the other specimens. It also comes from Bathonian aged sediments (Jurassic) and likely the same rock formation. The shell of the species is longer than wide with a flat anterior margin and no evidence of a sulcus. Typical of the Terebratulid order, there is a large, round foramen in the beak of the umbo on the pedicle valve.
Brachial valve
Anterior
Pedicle valve
Posterior
Profile
Thanks to Gery for sending me this fossil!
Brachial valve
Anterior
Pedicle valve
Posterior
Profile
Thanks to Gery for sending me this fossil!
Sunday, April 12, 2015
Amaltheus sp. ammonite from France
Here is another type of pyritized Ammonite that can be found in the Toarcian aged rocks (Jurassic) around Millau, Aveyron Dept., France. It's labelled as an Amaltheus sp. and is a small fossil. The whorls overlap about 25% of each previous volution. The external ornamentation is preserved well with the strong ribs that do not continue onto the keel. The keel is smooth except for a raised portion that has slight notches regularly space so that it looks like a braid from the side. Not enough of the internal sutures are visible to tell for sure, but this specimen looks very similar to one that I saw on the Steinkern.de forum, in this post, that was identified as Amaltheus margaritatus cf. forma subnodosus.
Thanks to Gery for sending me this fossil!
Thanks to Gery for sending me this fossil!
Friday, April 10, 2015
Pseudogrammoceras fallaciosum ammonite from France
Here I have a nice pyritized specimen of the ammonite Pseudogrammoceras fallaciosum. from the Toarcian aged rocks (Jurassic) near Millau, Aveyron Department, France. The gently curving external ribbing has been preserved as has the complex internal suture pattern. Each volution of the whorl covers approximately 60% of the previous. The specimen is missing the living chamber.
Another view of the complex sutures.
Thanks to Gery for sending me this fossil!
Another view of the complex sutures.
Thanks to Gery for sending me this fossil!
Wednesday, April 8, 2015
Leymeriella regularis ammonite from France
The fossil for today is Leymeriella regularis from the Albian stage (Jurassic) rocks near Bellegarde sur Valserine, Ain Department, France. The whorls are not overly wide but do cover approximately 90% of the previous generation. Moderate ribbing marks the sides of the whorls but does not continue completely across the keel of the shell. The cross section of the living chamber is square in shape.
Specimen #1
Specimen #2
Thanks to Gery for the specimens!
Specimen #1
Specimen #2
Thanks to Gery for the specimens!
Monday, April 6, 2015
Dorsoplicathoris dorsoplicata brachiopod from France
This is Dorsoplicathoris dorsoplicata from the Coronatum zone of the Callovian stage of the Jurassic, from near Villequiers, Cher department, France. It has a typical terebratulid shape and features, oval and with a large foramen on the umbo. The anterior margin of the shell is only slightly curved, meeting the side margins at an obtuse angle. That meet point is expressed as a shallow ridge along the surface of the valves pointing back towards the foramen.
Brachial valve
Anterior
Pedicle valve
Posterior
Profile
Thanks to Gery for the fossil!
Brachial valve
Anterior
Pedicle valve
Posterior
Profile
Thanks to Gery for the fossil!
Saturday, April 4, 2015
Lissoceratoides erato ammonite from France
Here is another ammonite from near Poitiers, Vienne Department, France. It's Lissoceratoides erato and is from Oxfordian aged rocks (Jurassic).
The whorls are wide and overlap each other quite a bit so that there is
just a small area in the center that gives evidence of previous shell. It is a fairly flat shell in cross section.
Here is a closeup of the shell and the visible sutures...
..and an image of the pattern lain flat.
Suture pattern image taken from "Renz O, Imlay R, Lancelot Y, Ryan WBF (1975)
Ammonite rich Oxfordian limestones from the base of the continental slope
off Northwest Africa. Eclogae geol Helv Vol 68 /2: 431–448"
Thanks to Gery for the fossil!
Here is a closeup of the shell and the visible sutures...
..and an image of the pattern lain flat.
Thanks to Gery for the fossil!
Thursday, April 2, 2015
Trimarginites trimarginatus ammonite from France
I apologize for the darker than usual photos of this specimen but I must have taken them on a cloudy day. they are of an ammonite called Trimarginites trimarginatus that comes from the Oxfordian stage sediments (Jurassic) near Poitiers, Vienne Department, France. The whorls are wide and overlap each other quite a bit so that there is just a small area in the center that gives evidence of previous shell. The cross section of the shell is flat.
The sutures are very complex. Here is a closeup of the shell and the visible sutures...
..and an image of the pattern lain flat.
Suture pattern image taken from "Renz O, Imlay R, Lancelot Y, Ryan WBF (1975) Ammonite rich Oxfordian limestones from the base of the continental slope off Northwest Africa. Eclogae geol Helv Vol 68 /2: 431–448"
The Ammonites.fr website has a page on this species that can be found here. Thanks to Gery for the fossil!
The sutures are very complex. Here is a closeup of the shell and the visible sutures...
..and an image of the pattern lain flat.
Suture pattern image taken from "Renz O, Imlay R, Lancelot Y, Ryan WBF (1975) Ammonite rich Oxfordian limestones from the base of the continental slope off Northwest Africa. Eclogae geol Helv Vol 68 /2: 431–448"
The Ammonites.fr website has a page on this species that can be found here. Thanks to Gery for the fossil!